Crow Substitution Jutsu

His substitution technique was unconventional. Normally, the ninja
switched out their own body for a log with a tag attached immediately before
an attack, in order to confuse their opponent. But rather than a log, Itachi’s
version used countless crows.

He had come up with the idea when he was training with Shisui, and saw a
flock of crows flying in the dense woods. If you used the usual log, the
confusion effect on your opponent was meager. But the instant you switched
out for crows, they flew off in all directions, so your opponent was surprised
and bewildered, generating an opening that wasn’t even on the same level as
with the log.

This was the first time he had tested it in an actual fight.
Will it work ... ?

He planned to do it when one of the three thrust a kunai into Itachi’s body.

Itachi Shinden: Book of Bright Light Chapter 1 Part 4